Scheduling communication in a wireless communication system

ABSTRACT

Interference may be determined between user equipment (UE) based on distance between the UEs and location information. Half duplex communication on orthogonal frequency division multiplexing (OFDM) resources may be scheduled based on the determined interference.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/883,687 filed Jul. 22, 2013, which is the National Stage Entry of PCTApplication PCT/EP2011/069663, filed Nov. 8, 2011, which claims priorityto GB Application No. 1019145.0, filed on Nov. 12, 2010, the entirecontents of which are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The field of this invention relates to scheduling communicationresources in wireless communication systems and in particular, but notexclusively, to scheduling half duplex (HD) frequency division duplex(FDD) communication in a 3rd Generation Partnership Project (3GPP™)cellular communication system.

BACKGROUND OF THE INVENTION

During the 1980s and 1990s, second generation (2G) cellularcommunication systems were implemented to provide mobile phonecommunications. 3rd generation (3G) cellular communication systems havebeen widely installed during the past decade or so, to further enhancethe communication services that may be provided to mobile phone users.The most widely adopted 3rd generation communication systems are basedon Code Division Multiple Access (CDMA) and Frequency Division Duplex(FDD) or Time Division Duplex (TDD) technology.

FDD means that the transmitter and receiver, in a given device or basestation, operate at different carrier frequencies. Uplink (UL) anddownlink (DL) frequencies/sub-bands are separated by a frequency offset.FDD can be efficient in the case of symmetric traffic such as voice andas a consequence many historical spectral allocations are paired for FDDoperation.

A full-duplex system, allows communication in both directions to/from abase station, and, unlike half-duplex, allows this to happensimultaneously. Land-line telephone networks are full-duplex, since theyallow both callers to speak and be heard at the same time. Two-wayradios can be, for instance, designed as full-duplex systems, whichtransmit on one frequency and receive on a different frequency.

A half-duplex system provides for communication in both directions, butonly one direction at a time (not simultaneously). Typically, once aparty begins receiving a signal, it must wait for the transmitter tostop transmitting, before replying. An example of a half-duplex systemis a two-party system such as a “walkie-talkie” style two-way radio,wherein one user must indicate an end of transmission, and ensure thatonly one party transmits at a time, as both parties transmit on the samefrequency, sometimes referred to as simplex communication.

A recent development in 3G communications is the long term evolution(LTE) cellular communication standard, sometimes referred to as 4thgeneration (4G) systems, which are compliant with 3GPP™ standards, whichwill be deployed in existing spectral allocations owned by NetworkOperators and new spectral allocations yet to be licensed. Irrespectiveof whether these LTE spectral allocations use existing 2G and 3Gallocations being re-farmed for fourth generation (4G) systems, or newspectral allocations for existing mobile communications, they willprimarily be paired spectrum for FDD operation.

In TDD systems, the same carrier frequency is used for both uplink (UL)transmissions, i.e. transmissions from the mobile wireless communicationunit (often referred to as wireless subscriber communication unit) tothe communication infrastructure via a wireless serving base station anddownlink (DL) transmissions, i.e. transmissions from the communicationinfrastructure to the mobile wireless communication unit via a servingbase station. In TDD, the carrier frequency is subdivided in the timedomain into a series of time slots and/or frames. The single carrierfrequency is assigned to uplink transmissions during some time slots andto downlink transmissions during other time slots. In FDD systems, apair of separated carrier frequencies is used for respective uplink anddownlink transmissions to avoid interference therebetween. An example ofcommunication systems using these principles is the Universal MobileTelecommunication System (UMTS™).

Typically, a wireless subscriber unit is ‘connected’ to one wirelessserving communication unit, i.e. a base station serving onecommunication cell. Transmissions in other communication cells in thenetwork typically generate interfering signals to the wirelesssubscriber unit. Due to the presence of these interfering signals adegradation of the maximum achievable data rate, maintained to thewireless subscriber unit, is typical. Such interference is oftenreferred to as ‘inter-cell’ interference.

However, within the communication cell, a wireless subscribercommunication unit may also observe/be affected by interference fromother wireless subscriber communication units communicating within thesame cell. Such interference is often referred to as intra-cellinterference.

The duplex spacing, between uplink (UL) and downlink (DL) frequencycarriers, and the duplex gap, i.e. the frequency separation between theuplink and the downlink band edges, often varies across the spectralallocations of FDD systems. In some instances, both the duplex spacingand the duplex gap can be set to be very narrow, for example with theduplex spacing ˜=2× channel bandwidth and the duplex gap ˜=1× channelbandwidth. In these instances half duplex operation of the mobile isdesirable or more often as not essential, as it is practicallyimpossible to achieve the required radio frequency (RF) filtering toperform full duplex FDD in a form factor that is compatible with thedecreasingly small size of a communication handset.

The primary reason for this phenomenon in a handset is that a duplexer(radio frequency separator/filter) that allows simultaneous uplink anddownlink operation, without interference from the other, is physicallynot realisable for cost and/or size reasons. In effect, the duplexermust, in the transmit path, essentially filter the adjacent channelleakage rejection (ACLR) emissions of the transmitter such that that thehandset's transmissions leaking into the handset's receiver chain arewell below the noise floor of the receiver. Furthermore, the duplexermust also, in the receive path, filter the transmit (UL) signal (in-bandand not out-of-band), so that it does not block the receiver.

Referring now to FIG. 1, a graphical example 100 of the aforementionedFDD HD problem is illustrated with regard to transmit power 105 versusfrequency 1 10. The UL transmit band 115 is shown as being adjacent theDL receive band 120. Within these frequency bands, paired narrowband ULtransmit channels 135 and DL receive channels 140 are allocated, with ULchannel transmissions that fall out-of-band for the downlink receivechannel being filtered 125 to an acceptably low power level by thereceive filter. UL adjacent channel emissions falling in-band for thedownlink channel are filtered 130 to an acceptable level by the transmitfilter. The paired nature of the narrow duplex Transmit-Receiveseparation (duplex spacing) 135 is also illustrated.

In the past, half-duplex systems, which were typically narrowband innature, have relied on a combination of channel filtering (at basebandfrequencies) and radio frequency (RF) band-filtering in the receiver inorder to provide sufficient selectivity to protect against inter-userinterference when two users are in close proximity. Thus, in HD FDDsystems, one communication unit is scheduled UL resource in a first timeslot whilst, for the same time slot, a second communication unit may bescheduled the DL resource. Taking, as an example, the TerrestrialEuropean Trunked RAdio (TETRA), allocated spectral bands at 400 MHz,there are 2×5 MHz allocations with a 10 MHz duplex spacing betweenuplink and downlink carriers or 5 MHz duplex gap. The TETRA systemoperates with a narrow channel bandwidth of 25 kHz across the 2×5 MHzspectral allocations, so in this scenario the downlink channel is manychannels away from the corresponding uplink channel. Thus filtering forfull duplex operation is feasible.

However, in considering a 5 MHz deployment of an LTE system in thisspectral band, the downlink channel will reside in the second adjacentchannel of the uplink. The default second adjacent channel performanceof an LTE user equipment (UE) is similar to that of a UMTS™ UE of thesame bandwidth at −43 dBc. If the transmit power of the UE is +23 dBm,this means that the adjacent channel power, without any specialfiltering measures, is −20 dBm. The noise floor of a reasonable UE istypically around −100 dBm. Thus, in order to cause less than a 3 dBnoise rise, the interference must also be at or below this level. Thus,a significant 80 dB additional selectivity (or RF signal rejection) isrequired from any duplexer or series of filters.

If, however, the use of TETRA in the 400 MHz band is replaced by abroadband data-oriented system, such as HD-FDD LTE, with a channelbandwidth of 5 MHz then filtering to the appropriate level 10 MHz awayis much more difficult, if not impossible to achieve, given the currentand projected state of the art in filter technology.

In a base station, where the size and cost of a duplexer is acceptable,the base station would still operate in full duplex communicationutilising all of the available frequency/time resource. In the basestation the aforementioned level of RF filtering can be achieved withmachined metal cavity filters, sometimes using dielectric resonators,which today cost around US$500 and have a significant size at sub-1 GHzfrequencies. Note that because the elements of these filters areproportional to the carrier wavelength their size increases withdecreasing frequency. Thus, such types of components would never besuitable for small form factor handset style devices, whereas fullduplex operation is still acceptable in a base station.

FIG. 2 illustrates an example of the timing 200 of full duplex FDD UEcommunications 200 and half duplex FDD communications 240. Asillustrated, the full duplex FDD UE communication 200 allows allocationof simultaneous UL transmit 210 from, and DL receive 220 time slots to,the UE. As illustrated, the Half Duplex FDD UE communications 240 do notallow allocation of simultaneous UL transmit 250 and DL receive 260 timeslots by a base station scheduler.

In a HD-FDD system the scheduler has the responsibility for notsimultaneously allocating the same uplink and downlink slots to a givenuser. This solves the intra-user interference problem (i.e. thescheduler can ensure that the UE does not transmit and receive at thesame time (or at least schedules time slots to allow sufficientswitching time between transmit and receive operation).

However, there is a possibility of an inter-user problem between twohandset devices if one user of a first handset is allocated a downlinkslot whilst another user of a second handset in close proximity to thefirst handset is allocated the same uplink time slot. This inter-userproblem is less serious than the potential intra-user problem due to thecoupling loss (in addition to any duplexer attenuation). However, it hasbeen appreciated that this can still present a serious problem if theinterferer is transmitting at high power and the victim handset is at acommunication cell edge.

Consequently, current techniques are suboptimal. Hence, an improvedmechanism to address the potential inter-user interference problem, forexample for a scenario where a new broadband system may be deployed inan historical spectral allocation traditionally used by a narrowbandsystem, would be advantageous.

SUMMARY OF THE INVENTION

Accordingly, the invention seeks to mitigate, alleviate or eliminate oneor more of the abovementioned disadvantages singly or in anycombination.

According to aspects of the invention, there is provided, a cellularcommunication system, methods of operation, integrated circuits andcommunication units adapted or configured to implement the conceptsherein described, as detailed in the appended Claims.

These and other aspects, features and advantages of the invention willbe apparent from, and elucidated with reference to, the embodiment(s)described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described, by way of example only,with reference to the accompanying drawings, in which:

FIG. 1 illustrates a known narrowband frequency division duplex (FDD)structure.

FIG. 2 illustrates a known radio full duplex (FD) and half duplex (HD)FDD framing/timing structure.

FIG. 3 illustrates a 3GPP™ LTE cellular communication system adapted inaccordance with some example embodiments of the present invention.

FIG. 4 illustrates a wireless serving communication unit, such as aneNodeB base station, adapted in accordance with some example embodimentsof the invention.

FIG. 5 illustrates a HD FDD system diagram and framing/timing structurein accordance with some example embodiments of the invention.

FIG. 6 illustrates an example of a flowchart to schedule HD FDDcommunication in accordance with some example embodiments of theinvention.

FIG. 7 illustrates a typical computing system that may be employed toimplement signal processing functionality in embodiments of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The following description focuses on embodiments of the inventionapplicable to a UMTS™ (Universal Mobile Telecommunication System)cellular communication system and in particular to a UMTS™ TerrestrialRadio Access Network (UTRAN) operating in any paired or unpairedspectrum within a 3rd generation partnership project (3GPP™) system.However, it will be appreciated that the invention is not limited tothis particular cellular communication system, but may be applied to anywireless communication system that may suffer from potential inter-cellinterference, for example in HD-FDD systems. However, in other examples,the inventive concept may be applied to adjacent channel TDD systems,for example in un-synchronised systems or when using uncoordinatedswitching points (UL/DL) within the frame and/or when performing jointscheduling between frequency carriers.

Referring now to FIG. 3, a wireless communication system 300 is shown inoutline, in accordance with one embodiment of the invention. In thisembodiment, the wireless communication system 300 is compliant with, andcontains network elements capable of operating over, a universal mobiletelecommunication system (UMTS™) air-interface. In particular, theembodiment relates to a system's architecture for an Evolved-UTRAN(E-UTRAN) wireless communication system, which is currently underdiscussion in the third Generation Partnership Project (3GPP™)specification for long term evolution (LTE), operating with ahalf-duplex frequency division duplex (HD-FDD) mode and described in the3GPP TS 36.xxx series of specifications.

The architecture consists of radio access network (RAN) and core network(CN) elements, with the core network 304 being coupled to externalnetworks 302 named Packet Data Networks (PDNs), such as the Internet ora corporate network. The main component of the RAN is an eNodeB (anevolved NodeB) 310, 320, which is connected to the CN 304 via S1interface and to the UEs 320 via an Uu interface. A wirelesscommunication system will typically have a large number of suchinfrastructure elements where, for clarity purposes, only a limitednumber are shown in FIG. 3. The eNodeBs 310, 320 control and manage theradio resource related functions for a plurality of wireless subscribercommunication units/terminals (or user equipment (UE) 325 in UMTS™nomenclature). As illustrated, each eNodeB 310, 320 comprises one ormore wireless transceiver unit 394 that is operably coupled to a signalprocessor module 396 and a scheduler 392 and communicates with the restof the cell-based system infrastructure via an 1_(ub) interface, asdefined in the UMTS™ specification. The series of eNodeBs 310, 320typically perform lower layer processing for the network, performingsuch functions as Medium Access Control (MAC), formatting blocks of datafor transmission and physically transmitting transport blocks to UEs325. In addition to these functions that the eNodeBs 310, 320 usuallyperform, the adapted schedulers 392 of eNodeBs 310, 320 are additionallyarranged to respond to demands for resource from the UEs 325 byallocating resource in either or both UL and/or DL time slots forindividual UEs 325 to use.

In one example embodiment, the eNodeBs 310, 320 operate in full duplex,whereas the UEs 325 are allocated resources to operate in a half duplexmode of operation.

In one example embodiment, the scheduler 392 obtains an indication ofuser location, for example by specifically requesting and receiving suchlocation information from a number of the UEs 325, or indeed by anyother means such as a repository of UE location information that isregularly updated and accessible to network elements within the system.

The CN 304 has three main components: a serving GW 306, the PDN GW (PGW)305 and mobility management entity (MME) 308. The serving-GW 306controls the U-plane (user-plane) communication. The PDN-GW 305 controlsaccess to the appropriate external network (e.g. PDN). In addition tothis operation, in one embodiment, the PDN-GW 305 is arranged to policethe DL AMBR for a number of non-GBR bearers that serve this particularUE-PDN connection. The MME 308 controls the c-plane (control plane)communication, where the user mobility, paging initiation for idle modeUEs, bearer establishment, and QoS support for the default bearer arehandled by the MME 308.

E-UTRAN RAN is based on OFDMA (orthogonal frequency division multipleaccess) in downlink (DL) and SC-FDMA (single carrier frequency divisionmultiple access) in uplink (UL), where the further information of radioframe formats and physical layer configuration used in E-UTRAN can befound in 3GPP TS 36.211 v.9.1.0 (2010-03), '3GPP Technical specificationgroup radio access network, physical channels and modulation (release9).

Each of the UEs comprise a transceiver unit 327 operably coupled tosignal processing logic 329 (with one UE illustrated in such detail forclarity purposes only) and communicate with the eNodeB 310 supportingcommunication in their respective location area. The system comprisesmany other UEs 325 and eNodeBs 310, 320, which for clarity purposes arenot shown.

In one example, the indication of user location may comprise one or morelow layer timing advance values, where the network may control thetiming of uplink transmissions from the UEs at different distances fromthe base station (eNodeB) in order to achieve synchronism at the basestation (eNodeB). In this manner, the network may derive round-trip timedistance information, or a path loss measurement such as SNR, SINR,CINR, BER, etc. made and reported by the UEs or higher layernetwork-based positioning information or global positioning system(GPS™) information.

In one example, the cell site (coverage area 385) supported by theeNodeB 310 may be tri-sectored (not shown), with three different cellsaround the site using independent scheduling to facilitate schedulingbased on propagation loss, which could result from a UE being anywhereon the edge of a cell, and not necessarily in the locality of ahigh-power transmitting UE 325.

Thus, based on the determined location information of UEs 325 within thecoverage area 385 of the eNodeB 310, the signal processor module 396determines a likelihood of interference from UL to DL channels betweenUEs. In one example, the signal processor module 396 employs a notion ofdetermining a safe (i.e. acceptable interference) distance between twousers, beyond which it may be deemed to be safe for one user/UE 325 totransmit on an uplink time slot and the other user/UE to receive thedownlink time slot at the same time, without interference occurring. Inone example, a determination or calculation of a safe (interference)distance may encompass a selectivity calculation (as indicatedpreviously) and may depend on one or more of several factors, such as:adjacent channel leakage rejection (ACLR), transmit power, acceptablenoise rise, etc. In one example, it is envisaged that ‘zones ofexclusion’ may be defined, using threshold levels, which may be of theorder of a 10 m-20 m radius from the user/UE and may be configured to bedynamically dependent upon the resolution of the distance measurement.

Following a determination or calculation of a safe (interference)distance by the signal processor module 396, the scheduler 392 mayperform a coordinated scheduling of multiple users/UEs 325, particularlytaking into account those users/UEs that are likely to be in closeproximity to one another. In particular, scheduler 392 pays attention tothose users/UEs 325 that may be within the safe distance of one anotherand configures the scheduling of resources such that those users/UEs 325are allocated simultaneous UL and DL time slots in UL and DLchannels/frames. In contrast, users/UEs that may not be within a safedistance of one another is/are not allocated simultaneous UL and DL timeslots in UL and DL channels.

Hence, in this manner, the eNodeB 310 is able to recognise and apply anotion of scheduling to avoid uplink-downlink time slot clashes in halfduplex (HD) systems based on a determination of an interferencepotential between the at least two UEs (wireless communication units)when they are respectively communicating with the eNodeB (base station).In one example embodiment, the scheduling may be configured to avoidinter-user interference by using location information such that thescheduler 392 does not schedule simultaneous UL and DL resource to usersthat could be in close proximity.

In one example embodiment, the above concept may be extended toincorporate other measures of an ‘ability to interfere’ into thescheduling. One example of this extension is to predict the transmitpower on the UL, and thereafter avoid the allocation of simultaneous ULand DL time slots/frames in the same area, or for scheduling UEs at thesame distance near a cell edge, where the ability to interfere isgreatest. In this example, the scheduler 392 may determine that two UEswere very close to the cell centre or site, and as such the potentialinterferer would be transmitting at a lower power (thereby leaving thevictim to have a greater signal to noise headroom). Thus, in thisinstance, taking into account power information, interference is muchless likely and simultaneous scheduling may be allowed.

In one alternative example embodiment, MME 308 or serving GW 306 maycomprise radio resource management (RRM) logic (not shown) which maycomprise a scheduler in addition to or instead of the eNodeBs' scheduler392. Here, RRM logic may instruct eNodeB 310 to inform the UEs 325 ofthe allocation of frequency resources, as illustrated in FIG. 5.Alternatively, in one example, the MME 308 or serving GW 306 maycomprise processing logic for instructing an eNodeB 310, 320 to allocatetime slots/sub-frames in the aforementioned manner. In this example, TheRRM logic may schedule HD FDD resources in UL and DL channels acrossmultiple cells/sites. In this regard, the RRM logic may utilize theusers/UEs location information to identify whether a plurality ofusers/UEs may be in close proximity to each other at edges of cells, butwhere they are being served by separate eNodeBs. In such a situation,RRM logic may schedule resources in UL and DL channels across multiplecells/sites to avoid inter-cell interference due to close proximityusers/UEs.

In one example embodiment, a signal processing module 396 may beconfigured to determine an interference potential between two users/UEsand may be arranged to repetitively perform such a determination on,say, a regular basis and/or dynamically in response to any locationupdate.

In one example embodiment, the scheduling or updating of a schedule maybe performed on at least one from a group consisting of a timeslot-by-time slot basis, a frame-by-frame basis, amultiframe-by-multiframe basis.

In one example embodiment, half duplex communication resource usage maybe monitored in the wireless communication system and based thereon thescheduler may selectably initiating at least one from a group consistingof: determining location information of at least two wirelesscommunication units of the plurality of wireless communication units;and determining an interference potential between the at least twowireless communication units when they are respectively communicatingwith the base station. Thereafter, the scheduler may schedule halfduplex communication resource to the at least two wireless communicationunits based on the results of the selectably initiated determination.

In one example embodiment, scheduling of half duplex communicationresource to at least two wireless communication units in close proximitymay comprise treating the at least two wireless communication units as asingle entity when scheduling half duplex communication resource andthereby avoiding scheduling the same resource to both of the at leasttwo wireless communication units simultaneously. In this manner, closeproximity wireless communication units will be treated as a group, withUL and DL resources allocated to the group. Internal to the group, ULand DL resources allocated to the group may be divided between thegroup, in an attempt to avoid simultaneous allocation of resources tothese close proximity wireless communication units.

Referring now to FIG. 4, a block diagram of a wireless communicationunit, such as eNodeB 310, adapted in accordance with some exampleembodiments of the invention, is shown. The eNodeB 310 contains anantenna or an antenna array 402 or a plurality of antennae, coupled toantenna switch 404 that provides isolation between receive and transmitchains within the eNodeB 310. One or more receiver chains, as known inthe art, include receiver front-end circuitry 406 (effectively providingreception, RF filtering and intermediate or base-band frequencyconversion). The receiver front-end circuitry 406 is coupled to one ormore signal processing module(s) 396. The one or more receiver chain(s)is/are operably configured to receive data packet streams in a pluralityof time frames.

A controller 414 maintains overall operational control of the eNodeB310. The controller 414 is also coupled to the receiver front-endcircuitry 406 and the one or more signal processing module(s) 396(generally realised by one or more digital signal processor(s) (DSPs)).The controller 414 is also coupled to or comprises (as shown) a buffermodule 417 and one or more memory devices/elements 416 that selectivelystores operating regimes, such as decoding/encoding functions,synchronisation patterns, code sequences, and the like. A timer 418 isoperably coupled to the controller 414 to control the timing ofoperations (transmission or reception of time-dependent signals) withinthe eNodeB 310.

As regards the transmit chain, this includes transmitter/modulationcircuitry 422 and a power amplifier 424 operably coupled to the antenna,antenna array 402, or plurality of antennae. The transmitter/modulationcircuitry 422 and the power amplifier 424 are operationally responsiveto the controller 414. The transmit chain is operably configured totransmit data packet streams to a plurality of users/UEs.

The one or more signal processor module(s) 396 in the transmit chain maybe implemented as distinct from the one or more signal processormodule(s) 396 in the receive chain. Alternatively, a single processormay be used to implement a processing of both transmit and receivesignals, as shown in FIG. 4. Clearly, the various components within thewireless communication unit (e.g. eNodeB 310) can be realized indiscrete or integrated component form, with an ultimate structuretherefore being an application-specific or design selection.

In accordance with example embodiments of the invention, the signalprocessor module 396 has been adapted to comprise logic 430(encompassing hardware, firmware and/or software) to determine whether alikelihood of interference in UL or DL channels with communicationsbetween the eNodeB 310 and multiple UEs. In one example, the logic 430may determine whether a safe distance exists between two users/UEs,beyond which it may be deemed to be safe for one user/UE to transmituplink communication and the other user/UE to simultaneously receivedownlink communication without interference occurring. Following adetermination or calculation of a safe (interference) distance, ascheduler 392 may perform a coordinated scheduling of users/UEs,particularly taking into account those users/UEs that are likely to bein close proximity to one another. In this example, scheduler 392 isshown as being functionally part of the signal processor module 396. Inother examples scheduler 392 may be distinct from, and operably coupledto, signal processor module 396. In particular, scheduler 392 paysattention to those users/UEs that may be within the safe distance of oneanother and ensures the scheduling of resources such that thoseusers/UEs are allocated simultaneous UL and DL time slots in respectiveUL and DL channels. In contrast, users/UEs that may not be within a safedistance of one another are not allocated simultaneous UL and DL timeslots in respective channels.

Referring now to FIG. 5, a simplified example of a HD FDD system 500 andframing/timing structure is illustrated in accordance with some exampleembodiments of the invention. Example embodiments of the inventionpropose to schedule HD FDD resource according to determined UE locationsand/or a perceived level of interference between UEs based on suchdetermined locations.

In this example, eNodeB 310 is communicating with (and allocatingresource to) at least three wireless subscriber communicationunits/terminals (or user equipment (UE) in UMTS™ nomenclature) 514, 516,517. As shown, UE3 514 is located close to (e.g. in the geographicalvicinity of) eNodeB 310. UE1 516 and UE2 517 are shown as being locatedclose to (e.g. in the geographical vicinity of) each other, and at theedge of the communication cell. Consequently, UE1 516 and UE2 517 areshown as being capable of causing potential interference 520 with oneanother, with little or no interference potential 515 being caused tocommunications between the eNodeB 310 and the first UE3 514.

Therefore, following a determination or calculation of a safe(interference) distance by a scheduler of the eNodeB 310, the eNodeB 310may perform a coordinated scheduling of UL time slot or frame resources505 and DL time slot or frame resources 510 to users/UEs, particularlytaking into account those users/UEs that are likely to be in closeproximity to one another, such as UE1 516 and UE2 517. In particular,scheduler pays attention to those users/UEs that may be within the safedistance of one another, such as UE3 514 and either or both of UE1 516and UE2 517. The scheduler then ensures that the scheduling of resourcesis such that those users/UEs are allocated/scheduled simultaneous UL andDL channels/frames, as illustrated. Thus, UE3 514 is allocatedsimultaneous DL or UL resources 505, 510 to geographically distal (andtherefore little/no interference potential) UEs, such as UE1 516 and UE2517. In contrast, users/UEs that may not be within a safe distance ofone another, such as UE1 516 and UE2 517, are not allocated/scheduledsimultaneous UL and DL channels/frames 505, 510.

Hence, the eNodeB 310 is able to recognise and apply a notion ofscheduling to avoid uplink-downlink time slot/frame clashes in halfduplex (HD) FDD or TDD systems based on a determination of aninterference potential between the at least two UEs (wirelesscommunication units) when they are respectively communicating with theeNodeB (base station). In one example embodiment, the scheduling may beconfigured to avoid inter-user interference by using locationinformation such that the scheduler does not schedule simultaneous ULand DL resource to users that could be in close proximity.

One benefit of the aforementioned techniques is to reduce or negate apotential impact of interference between UEs operating in half-duplexcommunications with a full-duplex operating NodeB. Modifications to anyexisting scheduling entity, whether within the eNodeB or any otherentity, may be applied that achieve one or more of the above benefits.Such modifications may involve re-configuring the radio resource control(RRC) layer and/or eNodeB Application Protocol (NBAP) in order toaccommodate the improved scheduling of UL and DL resources.Advantageously, no modification to the core network and associatedservices/applications are required to achieve the aims of theaforementioned example embodiments.

Referring now to FIG. 6, an example of a flowchart 600 to support halfduplex FDD scheduled communications between a base station and aplurality of wireless communication units is illustrated. The flowchart600 starts with the wireless communication system operating in halfduplex FDD communication on unicast channels, as shown in step 605. Ascheduler, for example a scheduler in a Node B base station, receives aresource request from a wireless communication unit, such as a UserEquipment (UE), in step 610. The base station then determines whether(or not) the base station has location information available for the UE,in step 615, for example previously stored location information orlocation information contained within the resource request. If the basestation determines that it does not have location information availablefor the UE, in step 615, the base station may make a request to the UEfor such information to be supplied to the base station, such as GlobalPositioning System (GPS) location information, as shown in step 620. Theflowchart may then loop back to step 615 and the base station may thensubsequently receive the requested location information, as shown instep 622.

If the base station determines that it does have location informationavailable for the UE, in step 615, the scheduler makes a determinationas to whether there is a likelihood of interference in either the UL orDL half duplex FDD channels with any other UE-base stationcommunication, based on the location information of the requesting UE,should simultaneous time slots/frames be allocated, as shown in step625. If the base station determines that there is a likelihood ofinterference in either the UL or DL half duplex FDD channels with anyother UE-base station communication, based on the location informationof the requesting UE, in step 625, the scheduler configures the HD FDDschedules for UEs, and particularly the requesting UE, to mitigate anypossible interference. In one example, the scheduler configures the HDFDD scheduling for UEs that are in close proximity to other UEs to avoidsimultaneous scheduling of UL and DL time slots/frames for those UEs.

Referring now to FIG. 7, there is illustrated a typical computing system700 that may be employed to implement software controlled schedulingfunctionality in embodiments of the invention. Computing systems of thistype may be used in wireless communication units. Those skilled in therelevant art will also recognize how to implement the invention usingother computer systems or architectures. Computing system 700 mayrepresent, for example, a desktop, laptop or notebook computer,hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe,server, client, or any other type of special or general purposecomputing device as may be desirable or appropriate for a givenapplication or environment. Computing system 700 can include one or moreprocessors, such as a processor 704. Processor 704 can be implementedusing a general or special-purpose processing engine such as, forexample, a microprocessor, microcontroller or other control logic. Inthis example, processor 704 is connected to a bus 702 or othercommunications medium.

Computing system 700 can also include a main memory 708, such as randomaccess memory (RAM) or other dynamic memory, for storing information andinstructions to be executed by processor 704. Main memory 708 also maybe used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor704. Computing system 700 may likewise include a read only memory (ROM)or other static storage device coupled to bus 702 for storing staticinformation and instructions for processor 704.

The computing system 700 may also include information storage system710, which may include, for example, a media drive 712 and a removablestorage interface 720. The media drive 712 may include a drive or othermechanism to support fixed or removable storage media, such as a harddisk drive, a floppy disk drive, a magnetic tape drive, an optical diskdrive, a compact disc (CD) or digital video drive (DVD) read or writedrive (R or RW), or other removable or fixed media drive. Storage media718 may include, for example, a hard disk, floppy disk, magnetic tape,optical disk, CD or DVD, or other fixed or removable medium that is readby and written to by media drive 712. As these examples illustrate, thestorage media 718 may include a computer-readable storage medium havingparticular computer software or data stored therein.

In alternative embodiments, information storage system 710 may includeother similar components for allowing computer programs or otherinstructions or data to be loaded into computing system 700. Suchcomponents may include, for example, a removable storage unit 722 and aninterface 720, such as a program cartridge and cartridge interface, aremovable memory (for example, a flash memory or other removable memorymodule) and memory slot, and other removable storage units 722 andinterfaces 720 that allow software and data to be transferred from theremovable storage unit 718 to computing system 700.

Computing system 700 can also include a communications interface 724.Communications interface 724 can be used to allow software and data tobe transferred between computing system 700 and external devices.Examples of communications interface 724 can include a modem, a networkinterface (such as an Ethernet or other NIC card), a communications port(such as for example, a universal serial bus (USB) port), a PCMCIA slotand card, etc. Software and data transferred via communicationsinterface 724 are in the form of signals which can be electronic,electromagnetic, and optical or other signals capable of being receivedby communications interface 724. These signals are provided tocommunications interface 724 via a channel 728. This channel 728 maycarry signals and may be implemented using a wireless medium, wire orcable, fiber optics, or other communications medium. Some examples of achannel include a phone line, a cellular phone link, an RF link, anetwork interface, a local or wide area network, and othercommunications channels.

In this document, the terms ‘computer program product’‘computer-readable medium’ and the like may be used generally to referto media such as, for example, memory 708, storage device 718, orstorage unit 722. These and other forms of computer-readable media maystore one or more instructions for use by processor 704, to cause theprocessor to perform specified operations. Such instructions, generallyreferred to as ‘computer program code’ (which may be grouped in the formof computer programs or other groupings), when executed, enable thecomputing system 700 to perform functions of embodiments of the presentinvention. Note that the code may directly cause the processor toperform specified operations, be compiled to do so, and/or be combinedwith other software, hardware, and/or firmware elements (e.g., librariesfor performing standard functions) to do so.

In an embodiment where the elements are implemented using software, thesoftware may be stored in a computer-readable medium and loaded intocomputing system 700 using, for example, removable storage drive 722,drive 712 or communications interface 724. The control logic (in thisexample, software instructions or computer program code), when executedby the processor 704, causes the processor 704 to perform the functionsof the invention as described herein.

In one example, a tangible non-transitory computer program productcomprises executable program code for scheduling half duplexcommunication in a communication cell of a wireless communication systemsupporting communication between a base station and a plurality ofwireless communication units. The executable program code may beoperable for, when executed in at least one from a group consisting of:a Core Network element, a radio resource manager (RRM), a Radio AccessNetwork element such as a base station, for example in a form of aneNodeB: determining an interference potential between the at least twowireless communication units when they are respectively communicatingwith the base station; and scheduling half duplex communication resourceto one or more wireless communication units based on the determinedinterference potential.

It will be appreciated that, for clarity purposes, the above descriptionhas described embodiments of the invention with reference to differentfunctional units and processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits or processors, without detracting from the invention. For example,functionality illustrated to be performed by separate processors orcontrollers may be performed by the same processor or controller. Hence,references to specific functional units are only to be seen asreferences to suitable means for providing the described functionality,rather than indicative of a strict logical or physical structure ororganization.

Aspects of the invention may be implemented in any suitable formincluding hardware, software, firmware or any combination of these. Theinvention may optionally be implemented, at least partly, as computersoftware running on one or more data processors and/or digital signalprocessors. Thus, the elements and components of an embodiment of theinvention may be physically, functionally and logically implemented inany suitable way. Indeed, the functionality may be implemented in asingle unit, in a plurality of units or as part of other functionalunits.

Those skilled in the art will recognize that the functional blocksand/or logic elements herein described may be implemented in anintegrated circuit for incorporation into one or more of thecommunication units. Furthermore, it is intended that boundaries betweenlogic blocks are merely illustrative and that alternative embodimentsmay merge logic blocks or circuit elements or impose an alternatecomposition of functionality upon various logic blocks or circuitelements. It is further intended that the architectures depicted hereinare merely exemplary, and that in fact many other architectures can beimplemented that achieve the same functionality. For example, forclarity the signal processing module 396 has been illustrated anddescribed as a single processing module, whereas in otherimplementations it may comprise separate processing modules or logicblocks.

Although the present invention has been described in connection withsome example embodiments, it is not intended to be limited to thespecific form set forth herein. Rather, the scope of the presentinvention is limited only by the accompanying claims. Additionally,although a feature may appear to be described in connection withparticular embodiments, one skilled in the art would recognize thatvarious features of the described embodiments may be combined inaccordance with the invention. In the claims, the term ‘comprising’ doesnot exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means,elements or method steps may be implemented by, for example, a singleunit or processor. Additionally, although individual features may beincluded in different claims, these may possibly be advantageouslycombined, and the inclusion in different claims does not imply that acombination of features is not feasible and/or advantageous. Also, theinclusion of a feature in one category of claims does not imply alimitation to this category, but rather indicates that the feature isequally applicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply anyspecific order in which the features must be performed and in particularthe order of individual steps in a method claim does not imply that thesteps must be performed in this order. Rather, the steps may beperformed in any suitable order. In addition, singular references do notexclude a plurality. Thus, references to “a”, “an”, “first”, “second”,etc. do not preclude a plurality.

What is claimed is:
 1. A user equipment (UE) comprising: a transceiver;a processor electrically coupled to the transceiver; wherein theprocessor is configured to: determine geographic position of the UEbased on satellite information and send the determined geographicposition to a network device; receive information on orthogonalfrequency division multiplexing (OFDM) resources in a time slotscheduled for half duplex communication, wherein the OFDM resources arescheduled based on an interference potential between the UE and anotherUE being located outside a vicinity of the geographic position; andwherein the another UE is scheduled to transmit information on the timeslot.
 2. The UE of claim 1 further comprising: the transceiverconfigured to receive, from the network device, a request to perform ameasurement related to the determined geographic position.
 3. The UE ofclaim 1 further comprising: the transceiver configured to receive, fromthe network device, timing advance information.
 4. The UE of claim 1,wherein the OFDM resources are scheduled in accordance with a transmitpower level of the UE.
 5. The UE of claim 1, wherein the OFDM resourcesare scheduled on a time slot-by-time slot basis, a frame-by-frame basis,or a multiframe-by-multiframe basis.
 6. The UE of claim 1, wherein theanother UE being located outside the vicinity of the geographic positioncomprises the another UE being located a distance from the geographicposition.
 7. A method performed by a user equipment (UE), the methodcomprising: determining, by the UE, geographic position of the UE basedon satellite information and sending the determined geographic positionto a network device; receiving information on orthogonal frequencydivision multiplexing (OFDM) resources in a time slot scheduled for halfduplex communication, wherein the OFDM resources are scheduled based onan interference potential between the UE and another UE being locatedoutside a vicinity of the geographic position; and wherein the anotherUE is scheduled to transmit information on the time slot.
 8. The methodof claim 7 further comprising: receiving, by the UE from the networkdevice, a request to perform a measurement related to the determinedgeographic position.
 9. The method of claim 7 further comprising:receiving, by the UE from the network device, timing advanceinformation.
 10. The method of claim 7, wherein the OFDM resources arescheduled in accordance with a transmit power level of the UE.
 11. Themethod of claim 7, wherein the OFDM resources are scheduled on a timeslot-by-time slot basis, a frame-by-frame basis, or amultiframe-by-multiframe basis.
 12. The method of claim 7, wherein theanother UE being located outside the vicinity of the geographic positioncomprises the another UE being located a distance from the geographicposition.